The elusive 224/3.7 MerCruiser banger

Yes indeed, that sounds perfectly reasonable.

If you can increase both airflow and peak power revs (without losing any volumetric efficiency) by 1.25, you get:
4,800 x 1.25 = 6,000 rpm
190Hp x 1.25 = 237 Hp.
Close enough to the rough rule of thumb 1Hp per inch at 6,000 value.

At 5,500 you might reasonably expect around 218 Hp.

And why to reach 360 Hp normally aspirated, you might need to increase both airflow revs by maybe x1.9:
That is a pretty tall order........
4,800 x 1.9 = 9,120 rpm, or more likely quite a fair bit faster than that.
190Hp x 1.9 = 361 Hp

 

If around twenty five percent lift in airflow, revs, and power, is your goal, you might need to increase cam duration by 8%, valve lift by 8% and valve and port area by 8%. That will get you very close. It never works out exactly like that in practice, but that would be the direction to head in.

 

I'll be happy with what ever the aluminum Procomp head will give me without screwing with anything else.

If for some reason I need more power I'll probably put a Buick Grand National turbo on it.

When Buick Engineers first set up the Grand National they got a car that was so fast that the Chevrolet Corvette Engineers screamed like mashed cats and made them tune it down a little.

The Buick was a 3.8 liter V6. The 470 is a 3.7 liter 4. Thats 6 cubic inches difference.

If I'm not mistaken the Grand National also used a 750 QuadraJet.

I'll bet that they would be fairly easy to hook up and that they wouldn't be hard to tune for the 470.

They are available at junk yards and are fairly reasonable.
.

 

Dick, That is good for an engine you actually are going to use on the street.
As my other engine began life getting 3mpg, I feel Randy's advice on intake resonance and lobe separation angles is well worth paying close attention to. (My other engine had intake manifold flow problems). Three carburetors and some jets later my other engine was up to 7 mpg. As a gas guzzler is of only limited use to me I went to an engine with a cam profile which held cylinder pressure longer, kept the 2bbl carb and decked the cylinders giving slightly more compression. I'm establishing an operational(saying "performance" is misleading in this case, but that is what it is about) benchmark to retain while making the other changes( eg, updraft carbs) that I need.

dennis

 

dennis,

The thing about a QuadraJet 4 barrel carburetor is that under moderate driving conditions only the primaries are used at 1.265" and when you need the extra power the secondaries open on vacuum.

The QJet is a large 4 barrel carburetor that has a small primary side for fuel economy and good emissions and a large secondary side for good performance.

QJets have a maximum airflow of from 750-800 cfm. Because the secondary side of the Qjet opens according to the airflow requirements of the engine, the same basic carburetor size can be used on a large range of engine sizes.

The basic 750 cfm QJet casting is used from 231 CID to over 400 CID - the big secondary air valves open only as the engine breathes. For example, on a mild 350 Chevy the air valve will never open all the way - because the motor can't use more than 600 cfm or so.

With the 470 only the amount of carburation required will be delivered but every bit that the engine requires is available.

I'm leaving the Mercruiser jets alone untill I can read the plugs. Then I will adjust if needed.
.

 

I used a single wire oxygen sensor [ from my derelict cavalier] to check mixture.
Only had to weld a sensor bung into the exhaust , screw sensor in and connect the wire to a digital multimeter I think they are a couple dollars from Harbor freight.
It worked much better than I expected. Set the meter on its lowest voltage and the sensor puts out about half a volt. Mine read 200 millivolts when it was lean and 700millivolts when it was rich. The voltage changed quickly between the two but it was a big help to me in jetting as it was so sensitive and I could see how the mixture was under different driving conditions .
It is definately worth doing.
----------------------------------------------
And the quadrajet is as you say. The vacuum secondaries in it make it possible to function well and be big too. I think you will like it.

However they look modern and take a lot of space. My car doesn't have room for a big downdraft carb . As a downdraft carb I like the autolite 2100 as it is so simple and is smaller. But even they are too big[ size not airflow].
So I will experiment with updraft carbs soon.

 

My motor is in my car's chassis.
Main mounts in and done, transmission mount to be made today.

A suggestion to my fellow builders, secure the block motor mount bolts very well.

I found that mine were backing out of the block, I had not torqued them but did use lockwashers. Now I will use red loctite, lockwashers, have them in tighter and when I'll have them out to apply the locktite, I will crossdrill their heads for saftey wire.

 

dennis,

I just removed the bellhousing on an early 470 and discovered a flywheel like the one you have.

It isn't drilled for the later model coupler but used studs that extend thru the flywheel and early coupler.

It looks like they used a regular ford flywheel as it is drilled for a pressure plate.

It looks like it is in very good condition as the ring gear hardly shows starter contact.

I will clean it up and use it on one of my projects

What transmission are you using?
.

 

I cleaned it up and only 3 bolt holes line up with my mustang pressure plates.

If I use it I will have to drill and tap 3 more holes.

I don't think it should be a problem because it is probably only regular cast steel.

 

Saginaw 3 speed. A standard old chevrolet transmission.

I caution you to avoid those from a pickup as the pickup low gear ratio is too low for a car. They can be identified by a larger diameter mating boss on the input end of the transmission. Pickup transmissions only fit pickup bellhousings [ unless you change the casting around the transmission input shaft].

My choice was easy:
These large 4 cylinder motors have lots of torque making a 5 speed transmission unnecessary. In my opinion, the extra two shifts only waste time, particularly in a light car. And as my shifter is not convenient to operate, the less shifting, the better. And 5 speed boxes are not like what was in the old cars.

 

Check again. All of them line up. Just go around and around until they line up.
I did not think they lined up either, but a parts guy showed me that they did.


My pressure plate is for 1984 mustang V8 [it is a perfect fit with no drilling].
Go to a parts store and try some for fit. The flywheel is easy to carry around.

All I had to do is scrape the black paint off of the pristine flywheel friction surface.

 

There are several throwout bearings that fit in there, but only the long one* will disengage the clutch. I did not know that on my first engine and ended up making a special throwout ball stud.

* it is really long, about twice as long as the others. I'll post a part # for it.

 

several engines that i had came with a flywheel with a ford part number o them,complete with bolt holes for a clutch etc.

 

Please do! I was about to start that exact search!

 

dennis,

I have come to the conclusion that the 84 pressure plate must be different than the two that I have that fit the later model zero balance flywheels.

I will try an 84 mustang pressure plate.

Thanks for the info on the 84 plate.

I bought a complete later model set, zero balance flywheel, clutch disk, Hays pressure plate and throw out bearing on ebay a year or so ago.

I have lost the name of the supplier but they were very reasonable.

I need to start a file to keep track of suppliers and costs.

It used to be that I could recall that information years later.

Now by the time it's delivered I have almost forgotten that I ordered it.
.

 

part number for throwout bearing : SKF N1086-SA or FM 614037

mine was a Chinese bearing: Precision # 0326J

Get your bearing [ or several with the right to return it for a full refund if it does not fit.] So the sales guy will say whats it for? When you say boat motor he will understand why it must be a trial and error procedure. It will still be that with the above number as your stuff may be different, But that bearing works for two of my engines.

In stores I go to they usually bring a dozen boxes out and say "Will any of these fit?",Or they will direct me to the parts storage area and let me open the boxes.

 

I ordered a package and it arrived while I was still thinking about ordering it.

Now I walk 30 feet and on arrival, wonder what purpose there was for me to go there.

 

They are only sold as sets now, but you can still make that work for you because the other guys have to buy a full set to get the single part they need. So, look on ebay where they dispose of their extra new parts.My pressure plate cost me $25 plus freight,I think the disk was about $20 plus freight.


But go down to Carquest and see what fits your flywheel before ordering on Ebay.

 

Another thought, I did not have a 2bbl throttle linkage and decided to buy one rather than make one as I usually do. As it changes direction and goes around a corner, it would have been difficult to make well so I advise using the Mercury part.

I finished my transmission mount this evening. A new firewall will be next and moving the steering, brake cylinder support, and throttle pedal assembly.

 

I do know (from my past life as a Napa guy) that in 86 Mustang flywheels and clutches changed just a bit- about a 1/2" bigger, but altogether different, no parts interchange. So the split is 78-85, and 86-94, when they abandoned the 5.0.
This is from memory, so going with 1984 sounds safe.
The Ebay supplier I bought my stuff from is "GripForce". Asian made, but a very good grade of Asian-made...& great service.

Thank you for pointing out the "1086" release bearing. I realized that I am using the Jeep "Iron Duke to T4/t5" bellousing, and thus fork. I know the OE bearing for that fork clipped on, whereas the Ford one does not. I will have to see if that creates any assembly issues. It's these details that are so time consuming. Sounds like a few of you are retiree's... That would definitely help some aspects of this. I'm 37, and working 55-60 hrs most weeks.

 

the 1086 clips on.
You are a busy guy working that much.
I'm 70, retired many years. Loving it.
Got my firewall frame about half done today, had to dodge some rain.
Had to redo it as it was too wide, so 3 days of cutting, welding, notching and grinding and it is in.

 

Rain is the least of my problems. Found that my firewall frame was 3" too wide.Naroiwing it meant that the car'sclutch pedal would occupy the same space as the firewall support. So now I'm rebuilding it with a dogleg in it to leave room for the clutch pedal.
In retrospect, an automatic transmission would have been easier to fit into a tiny car as it has the advantage that there is no clutch linkage to fuss with. They are big and heavy tho. but with manual valving controlling the transmission they'd be more acceptable.

Wonder what the actual weight difference is?
my 3 speed box weighs about 87 lbs
add weight for flywheel 12 lbs? [guessing ]
add weight for clutch disk 3 lbs? [guessing]
add weight for pressure plate 25 lbs? [guessing]
130 estimate

As an example, a short tail TH350 weighs about 125 lbs to this you'd have to add the wt the torque converter . I'd estimate that total to be around 150-155 lbs

So the manual one would weigh only a little less.
comparing lengths, the 3 speed is roughly 5" shorter than the TH350

 

I would expect a flywheel and clutch to weigh about the same as a torque converter full of fluid.
So probably not a huge difference, especially with a cast iron manual gear case.
One other consideration is the narrow foot well in some rods, where there is limited room for that third pedal.

 

I now have a Federal Mogul N1086 "equivalent" on my desk. It doesn't clip on, and I am not really sure it is the one you meant.
Here are a couple links to photos. Sorry to be helpless here, but my project is in storage about a half hour away, plus I do not have the crank turned for a pilot bearing yet, so there was no point to checking for depth... so I didn't go there last night.
This doesn't use a clip, it uses a raised "ridge" at one point to prevent turning. Again, since I haven't checked, I don't know how this will work with my fork.
I am just wondering if you could absolutely confirm the number and brand you have?
pics:
http://frugalmechanic.com/auto-part/skf-n1086sa--skf-n1086-sa-ball-bearings-clutch-release-unit shows the ridge @ "11:00"
http://www.summitracing.com/parts/CTF-N1086/
BTW, & 'fwiw', the second link gives this as application of 68-77 GM, mainly SBC/BuickV6/ChevL6.

 

I am in the marine business and I will tell you straight up that these were the worst engines that Merc ever used this was Mercury's atempt to produce their own engine in house.. Every thing from blown head gaskets, major over heating, starting isues, Enough already they are like owning an Edsel or the GM Monza. JMO so don't take offense but those little bast__ds caused us a lot of grief over the years.

 

Get over it. They have thier quirks but when properly set up they are fine motors.

 

Bigdaddyhemi,

There were 2 problem areas with the Mercruiser engineering.

Both stem from Mercury engineers trying to stay with their no belt unified engine.

The outboard motors that they were used to engineering had the alternator and water pump built in.

So they incorperated the alternator into the Harmonic balancer on the front of the engine.

They used a water cooled Rectifier regulator combination.

The Stator windings inside the Magnetic harmonic balancer were subject to exposure to water and other damaging possabilities.

The regulator was also problematic and expensive.

Both of those problems are easily addressed by replacing them with a belt driven alternator.

They also incorporated the water pump into the engine by driving it off of the front of the cam shaft.

They provided 2 water seals in the front engine cover to keep water from entering the crank case.

The first seal actually sealed the water pump.

The second seal was a safety seal designed to give the operator warning of emminent system failure.

When the first seal leaked the water passed into a safety chamber before meeting the second seal.

A drain hole allowed the green antifreeze water to spill into the bottom of the boat giving a warning to the opperator to replace both seals.

Several problems developed from this arrangement.

Coolant was not changed as suggested in the owners manual and some owners didn't read the manuals.

Some mechanics reported that owners had plugged up the warning drain to stop the water leak apparantly not knowing the emminent danger.

This problem can be easily solved by cutting off the water pump extension on the cam shaft, plugging the front cover where the shaft came out and using a electric or belt driven pump.

The only other potential problem is over heating causing the cast iron 460 ford head working on the head gasket at a different expansion rate than the aluminum block.

Again proper maintenence and proper attention would prevent most of the problems.

With a cold water heat exchanger available as in a boat overheating is probably an operator error problem.

In a car the problem is different using a radiator as it is much harder to keep the temp low.

The expansion differential between aluminum and cast iron is not that great at 160 to 180 degrees but when engines with this combination over heat head gaskets fail.

The best solution is to buy an aluminum performance head and get the benefit of having aluminum on aluminum, larger valves and ports and the added benefit of the aluminum head running cooler by nature.

Anyway I understand your concern and you are in good company because many owners and mechanics had problems with these engines.

However understanding the potential problems and working thru them will provide a very robust light weight engine.

Many people have raced these engines with great sucess and have over stressed them in doing so.

Randy Dupree raced one seven years and finally blew his up after completing a 187 mph one way at the salt flats.

Sarge Nichols from inliners has built 3 of them for the drags.

I have talked to many owners of 470 who swore by them not at them.

They reported low gas consumption and good performance over many years of use.

.

 

reading off the box in my hand:

brand "precision"

" replaces FM 614037 "

"replaces SKF N1086-SA "

" made in china "
" 0326J 3"


barcode " 6 82034 61382 3 "


it looks like the photos you referred to
the bump prevents rotation on them
the clip is part of the throwout fork,
it engages the thin lip on the transmission end of the throwout bearing.

I've the box in my hand, took a photo of it to send to you, but this computer does not recognize the camera and the other one is not recognized by this website, am stuck but will persevere.

I think you have the right bearing.
Does your fork have a thin spring steel clip?
If not,I'd get another fork,
mine was $18 new on ebay

 

Like I say, I need to put some time in at the garage, which is not at home or work! Don't worry too much about the photo just yet. Since the numbers do look right, I will continue.

I have the cam down in the US (I live in Canada), and have settled everything, or almost everything, with Lunati to have the cam reground- a very quick acting "fat" lobe 265/271 (220/226) hydraulic

 

Yes there were design quirks in it.
Some can be lived with.
Others need to be remedied.

1. I changed my flywheel alternator only because one weight fell out.

2. The water pump i have changed
3. The squish area warrants immediate attention. as my block was being milled anyway. My compression is now 175 on all cylinders[cold]
It ran 600 miles on regular pump gas and did not knock...ever.
Its stock starter flings it madly around but I can change to a mini gear-drive one to save lbs.
If weight is ever an issue, alloy head is good option saves about 35 lbs

But I'm happy with mine as:

1. its rods are really strong and I can trust it not to fly apart when I get on the throttle. *
2. with its crossflow head I don't have to fight intake manifold sealing.*
3. It has the high compression ratio that I so desperately need*.
4. Even with an iron head, it is still 200 lbs lighter than an equivalent iron engine.*

*Its predecessor had expensive problems in each of these 4 areas and also leaked antifreeze into the oil through a corroded "O ring" land and tended to loose oil pressure suddenly.

Its quirks seem minor to me. Especially after what I've been through.

Expect an update after I drive it[ in 2weeks].